Institute of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan.
Langmuir. 2010 Dec 7;26(23):17943-8. doi: 10.1021/la1030747. Epub 2010 Oct 28.
In order to prepare SiO(2) nanoparticles that are dispersible in various organic solvents, an anionic surfactant 1, which branches into a hydrophobic chain and a hydrophilic chain, was adsorbed on to SiO(2) nanoparticles through a layer-by-layer surface modification route using polyethyleneimine (PEI). First, the relationship among the additive content of PEI, adsorbed content of PEI, and the redispersion stability of the SiO(2) nanoparticles in water was investigated. While almost the entire PEI was adsorbed when the additive PEI content was lower than 67 mg/g of SiO(2), the adsorbed content of PEI became saturated when the additive content was increased above 90 mg/g of SiO(2). SiO(2) nanoparticles that were saturated with PEI could be redispersed into water at sizes close to their primary particle size without the large-scale formation of aggregates. Next, the anionic surfactant 1 was adsorbed on the SiO(2) nanoparticles by using a SiO(2) aqueous suspension saturated with adsorbed PEI. It was found that the adsorbed content of 1 increased almost linearly as the additive content was increased when the additive condition was below 1400 mg/g of SiO(2). Furthermore, SiO(2) nanoparticles adsorbed with 80 mg/g of SiO(2) of PEI and 810 mg/g of SiO(2) of 1 could be dispersed into various organic solvents with different polarities. This layer-by-layer modification technique can also be applied to Ag nanoparticles in order to prepare Ag nanoparticles that can be dispersed in various organic solvents.
为了制备在各种有机溶剂中可分散的 SiO(2)纳米粒子，通过使用聚乙烯亚胺（PEI）的层层表面改性方法，将一种带有疏水链和亲水链的阴离子型表面活性剂 1 吸附到 SiO(2)纳米粒子上。首先，研究了 PEI 的添加量、PEI 的吸附量以及 SiO(2)纳米粒子在水中的再分散稳定性之间的关系。当添加的 PEI 含量低于 67mg/gSiO(2)时，几乎全部的 PEI 被吸附，但当添加量高于 90mg/gSiO(2)时，PEI 的吸附量达到饱和。用 PEI 饱和吸附的 SiO(2)纳米粒子可以重新分散在水中，粒径接近其原始粒径，而不会形成大的聚集体。接下来，通过使用吸附有 PEI 的 SiO(2)纳米粒子的水悬浮液来吸附阴离子型表面活性剂 1。发现当添加条件低于 1400mg/gSiO(2)时，随着添加量的增加，1 的吸附量几乎呈线性增加。此外，用 80mg/gSiO(2)的 PEI 和 810mg/gSiO(2)的 1 吸附的 SiO(2)纳米粒子可以分散到具有不同极性的各种有机溶剂中。这种层层修饰技术也可以应用于 Ag 纳米粒子，以制备可分散在各种有机溶剂中的 Ag 纳米粒子。
